The present invention relates to a surgical table for use in a hospital operating room, and particularly to a surface pad system for a surgical table, the surface pad system being carried by a generally horizontal upwardly-facing table-top surface of the surgical table and being positioned to lie beneath the patient. More particularly, the present invention relates to a surface pad system that can regulate the temperature of the patient, assist in positioning the patient, and that minimizes the interface pressure between the patient and a patient-support surface of the surface pad system thereby minimizing the occurrence of pressure ulcers and neuropathy caused by prolonged exposure of the patient to high interface pressures between the patient and the patient-support surface.
It is known to provide surface covers for operating tables for supporting patients above a table-top surface of the surgical table. Conventional surface covers typically include a foam rubber core surrounded by ticking material. It is also known to provide a gel pad between the foam rubber and a top panel of the ticking material covering the foam rubber. In addition, these operating table surface covers are typically provided in the form of a set of pads including a head pad supporting the head of the patient, a body pad supporting the torso of the patient, and a foot pad supporting the lower legs and feet of the patient. Occasionally, these sets include a fourth pad positioned longitudinally between the body pad and the foot pad and supporting the sacrum of the patient.
It is also known to provide a patient support having an upwardly-facing top surface, the temperature of which is controlled. For example, U.S. Pat. No. 5,402,542 to Viard, which is assigned to the assignee of the present invention, discloses a fluidized patient support having a temperature-controlled top surface supporting the patient.
It is also known to provide inflatable bladders and inflatable cushions in mattresses which can be inflated and deflated to assist a caregiver when tuning a patient relative to the sleeping surface of the mattress. For example, U.S. Pat. No. 5,269,0302 Pahno et al. discloses an apparatus and method for managing waste for patient care, the apparatus including inflatable sacks which assist turning the patient to facilitate cleansing of the patient. In addition, U.S. Pat. Nos. 4,949,414 and 5,062,167 to Thomas et al., which are assigned to the assignee of the present invention, disclose a bi-modal turning method that utilizes a mattress including a plurality of identical multi-chambered inflatable sacks.
What is needed is a surface pad system for a surgical table that can assist with the regulation of the temperature of the patient on the patient-support surface, that can position the patient, and that minimizes the interface pressure at high pressure points between the patient and the patient-support surface. The patient-support surface of the surface pad system should be conformable to fit the contours of the patient and maximize the surface area of contact between the patient-support surface and the patient, thereby minimizing the interface pressure between the patient and the patient-support surface.
The surface pad system should also be capable of moving or rolling the patient from an initial position to a new position without requiring the members of the surgical team to reposition the anesthetized patient and without requiring the members of the surgical team to stuff pillows, towels, wedges, or other objects between the patient and the patient-support surface while manually holding the patient in the new position to keep the patient in the new position after the members of the surgical team stop holding the patient. In addition, once the patient is moved to the new position, the surface pad system should rigidly support the patient in the desired position. Finally, the patient-support system should maintain the patient at a comfortable temperature while the patient is awake, and once anesthetized, the patient-support system should assist in reducing the temperature of the patient to the desired operating temperature selected by the surgical team.
According to the present invention, a surface pad system is provided for a surgical table. The surface pad system includes a cover having an upwardly-facing patient-support surface, the cover defining an interior region of the surface pad system. A vacuum bead bag is received in the interior region of the surface pad system. The vacuum bead bag includes a flexible cover defining an interior region containing compressible beads. A bladder is received in the interior region of the cover and is positioned to lie beneath the vacuum bead bag. The bladder defines an interior region of the bladder and is inflatable when pressurized fluid is received in the interior region so that the vacuum bead bag conformingly engages the patient on the patient-support surface when the bladder is inflated.
In preferred embodiments the surface pad system includes a plurality of pad sections that are positioned to lie on the upwardly-facing table-top of a surgical table between the patient and the surgical table. The preferred surface pad system includes a head pad section positioned to lie beneath the head of the patient, a leg pad section longitudinally spaced apart from the head pad section and positioned to lie beneath the lower legs and feet of the patient, a body pad section positioned to lie between the head pad section and the leg pad section, and first and second arm pad sections each of which is positioned to lie beside the body pad section and beneath an arm of the patient.
Each pad section of the surface pad system includes a pad core received by a cover of the pad section. Each pad core includes a plurality of pad core elements. Preferably, each pad core includes a base foam support layer made from high density foam that is positioned to lie beneath the other pad core elements and that provides a structural foundation for the pad core.
Each preferred pad core also includes a bladder pad having one or more bladders in fluid communication with a pressurized fluid source and inflatable to a first pressure for pressing the patient-support surface against the patient to conform to the shape of the patient when the bladders are inflated to the first pressure. In addition, selected bladders can be inflated to a second pressure which is greater than the first pressure. Each selected bladder can be arranged relative to the pad section so that when the bladder is inflated to the second pressure, the bladder and the patient-support surface reposition the patient from an initial position to a new position by raising the portion of the patient-support surface above the bladder from its initial position to a higher position and repositioning the patient, for example, by causing the patient to tilt or roll away from the bladder. If desired, the bladder can be subsequently deflated to reduce the pressure in the bladder to the first pressure and causing the patient to move back to the initial position.
Also, each preferred pad section includes a vacuum bead bag which is preferably positioned to lie on top of the bladder pad. The vacuum bead bag includes a casing forming an interior region containing a plurality of tubes, each of which is filled with compressible beads. The interior region of the vacuum bead bag is in fluid communication with a vacuum source. When air is evacuated from the interior region of the vacuum bead bag, the compressible beads are compressed against one another and deform so that the beads are held immobile with respect to one another and the vacuum bead bag rigidly assumes the shape that it is in when the interior region is evacuated.
The vacuum bead bag in accordance with the present invention includes an upper layer of elongated tubes containing compressible beads and a lower layer of elongated tubes containing compressible beads. Each tube in the lower layer of the vacuum bead bag extends in a first direction. Each tube in the upper layer of the vacuum bead bag extends in a second direction. The second direction is different from the first direction, and preferably the second direction is generally perpendicular to the first direction. This "plywood" arrangement provides an extremely rigid support when the interior region of the vacuum bead bag is evacuated. By layering the tubes in the criss-crossing plywood arrangement with "grains" of each layer running in generally perpendicular direction provides support for the patient both in a longitudinal direction and in a lateral direction.
Each pad section of the surface pad system also preferably includes a pressure-reduction foam layer made from foam rubber which is positioned to lie on top of the vacuum bead bag. The pressure-reduction foam layer is made from a thermally active "visco-elastic" foam rubber material. When the foam layer is at a warmer temperature the foam is softer and more pliable and when the foam layer is at a cooler temperature the foam is harder and retains its shape.
When a patient is awake and the patient-support surface in maintained at a comfortable warm temperature, the visco-elastic pressure-reduction foam layer will tend to conform to the shape of the patient. After the patient is anesthetized and the temperature of the patient-support surface is lowered, the visco-elastic pressure-reduction foam layer will tend to retain its shape. Thus, if the position of the patient is changed during the course of a surgical procedure, once the patient is moved back into his or her original position, the pressure-reduction foam layer will have generally retained its original shape and thus will be shaped to receive the patient.
Each pad section of the surface pad system also includes a thermal pad which is preferably positioned to lie above the pressure-reduction foam layer. The thermal pad is positioned to lie above the pressure-reduction foam layer to maximize the effectiveness of the heat transfer between the thermal pad and the patient-support surface and to minimize the impact of the thermally insulating pressure-reduction foam layer on the heat transfer between the thermal pad and the patient-support surface.
The thermal pad includes a serpentine-shaped channel defined therein. A thermoregulation fluid is received in the channel and is circulated through the channel to maintain the temperature of the thermal pad and thus maintain the temperature of the patient-support surface near the temperature of the thermoregulation fluid. The channel is in fluid communication with a heat exchanger so that the temperature of the thermoregulation fluid, and thus the temperature of the patient-support surface, can be adjusted according to the desires of the surgical team by using the heat exchanger to adjust the temperature of the thermoregulation fluid flowing through the channel.
A gel pack is positioned to lie on top of the thermal pad. The gel pack includes a casing containing a viscous material such as a silicon polymer of the type used to produce prosthetic devices. The viscous material will tend to flow away from high interface pressure points and will tend to flow toward low interface pressure points, thus more evenly distributing the weight of the patient and buoying the patient away from the high interface pressure points, thereby minimizing the interface pressure between the patient and the patient-support surface at the high interface pressure points. Preferably, a thermocouple is positioned within the gel in the gel pack to provide feedback to the heat exchanger controlling the temperature of the thermoregulation fluid.
A cut-proof material is positioned to lie above the gel layer. The cut-proof material operates to protect the pad core, and particularly the gel layer, the thermal pad, and the bladder from puncture due to dropped scalpels, dropped needles, or other sharp objects. In addition, the cut-proof material is preferably placed along the sides of each pad section to provide additional protection against punctures and cuts.
The cover is formed to include an interior region surrounding the pad core and holding the pad core elements in place relative to one another. Preferably, the cover is made from a bidirectional stretch material that can be stretched both in a longitudinal direction and in a lateral direction. Use of a bidirectional stretch material eliminates folding of the cover material on itself during movement of portions of each pad section relative to other portions of each pad section. In addition, the cover is preferably made from a liquid impermeable material to both protect the pad core elements from exposure to fluids from outside of the cover and to protect the patient from exposure to fluids from the pad core elements in the event of rupture of the gel pack, the thermal pad, or one of the bladders. If desired, a fire proof sock c an be positioned to lie between the pad core elements and the cover to assist with extinguishing flames after the pad core elements are exposed to flames, a characteristic required by regulations imposed by several regulating authorities.
The pad sections can be configured so that each pad section couples to each other pad section. For example, the head pad section can be coupled to the body pad section and the body pad section can be coupled to the leg pad section and both of the arm pad sections. Preferably, the channels formed in the thermal pads of each pad section are in fluid communication with one another so that the thermoregulation fluid circulates through the thermal pads of each pad section. Circulating the thermoregulation fluid through the thermal pad of each pad section allows for the temperature of the thermoregulation fluid to be regulated by a single heat exchanger rather than including a separate heat exchanger for the thermal pad of each pad section.
Likewise, the vacuum bead bag of each pad section can be in fluid communication with the vacuum bead bag of each other pad section. This coupling permits the use of only one vacuum source which is used to operate the vacuum bead bags of each pad section. Also, although the bladders in each of the pad sections are not in fluid communication with one another, the bladder pad in each pad section is formed to include an internally contained channel system eliminating the need to include hoses connected to each bladder. The channel system allows for the use of a single pressurized fluid source which can inflate and deflate the bladders of each pad section.
A controller is provided for the surface pad system in accordance with the present invention. The controller is used to control the operation of the heat exchanger, the vacuum source, and the pressurized fluid source. The use of a single controller to control each of the heat exchanger, the vacuum source, and the pressurized fluid source allows for the coordination of each of these systems. For example, the controller can be programmed to lower the temperature of the patient-support surface during surgical procedures at a predetermined cooling rate. However, if desired, the lowering of the temperature can be programmed to occur only after the bladders are inflated and after air is evacuated from the vacuum bead bags. In addition, a "chest-expanding" bladder can be provided in the body pad section which can be pressurized to hyperextend the chest cavity of a patient during surgical procedures. If desired, the controller can be programmed to allow this inflation of the chest-expanding bladder only after the temperature of the patient-support surface has been lowered to the desired operating temperature by the thermoregulation fluid in the thermal pad.